Two Shivas or one Blueprint 1503?

[Wayne P]

Hello,

First post here, so please be gentle with a noob. I know I’m probably a pretty lame DIYer compared to the rest of you guys, but here goes.

Here’s the deal: Currently I have a pair of passive 12” Shivas, each in a 2.5 cubic ft. sealed box. The boxes are old tower speakers that I drafted for the job because they were laying around, and they’re stacked on their sides in a corner. Yes, it looks pretty pitiful.

I have a chance to get from a friend a passive sub in a nice-looking 3.5 cubic ft. box. It has a 15” driver in it. However, I’ve never been particularly impressed with the way this thing performed at his place, so I’d probably like to replace the driver with something more capable.

I love the two Shivas, but they struggle in my huge room (6200 cubic ft.) on the most demanding action flicks, since I‘ve had to equalize them pretty drastically to get solid extension down to 25Hz. So it would be nice if I could not only make a visual improvement, but also a performance improvement. I don’t think the latter would have to be drastic – probably a 15-20% improvement would be more than adequate.

I posted this question on another forum and someone recommended the Blueprint 1503 as a driver in a box that size that would deliver the goods as well or better than the two Shivas. I would like do know what you folks think about this, or perhaps recommend a different 15” driver for me.

Thanks in advance.

Regards,
Wayne A. Pflughaupt

[mikee12345]

Well your problem is in the alignment not the driver
You arent getting the optimal response from the shiva

2.5cubes sealed has no lows,and your expecting lows and EQINg it , very bad. EQing a sealed box will result in extremely high excursion,limiting SPL .

Atleast if u EQ a ported box near its tuning the excursion doesnt increase TOO badly...

Can you fit 4 cubes ported for each sub?


btw 2 12"s have same area as 1 15" ,so then all u can do to compare is-
-box size compare(in the right box for each)
-Volume displacement
-Sound quality of each

Cheers!

edit=each horizontal line on that graph is 6db

[kelticwizard]

Wayne:

Are they still making Blueprints? If so, where can you get them.

[jackinnj]

the moonless night in February -- for those of you who have studied your comparative theology.

[Tieftoener]

mikee12345 is right on. You want to put those things in a vented ~3.3 ft^3 cabinet, or perhaps slightly different vented. Look at the Shiva Whitepaper for more info. For HT, you definetly want to go vented. I recommend one of the big flared ports for this job - when my Shiva's are crankin, they move A LOT of air. I actually only have one in my HT now, filling a room of ~4000ft^3. And it's more than enough, even with action from Terminator 3 or the like.

Good luck,

[kelticwizard]

Originally posted by mikee12345

btw 2 12"s have same area as 1 15" ,so then all u can do to compare is-
-box size compare(in the right box for each)
-Volume displacement
-Sound quality of each

Cheers!

Actually, Mike, I think the rule of thumb is that two 10 inchers have the same cone area as one 15 incher.

Two 8 inchers have the same cone area as one 12 incher.

But you are not so far off.

[mikee12345]

oh oooops,whats 200cm^2 between fellow diyers:P

acoustic-visions sells blueprint apprently,see the diysubwoofers.org forum

Gota run!

[ThomasW]

Some of the original BluePrint drivers are still available HERE

Also there is some online chatter that production will start up again